Pitch actuators for controlling the pitch angle of one or more rotor blades of a wind turbine are widely known within the technical field.
Each rotor blade is influenced by disparities e.g. due to production variations in the actuator, various tolerances pitch actuator components, variations in blade bearing friction e.g. originating from mounting differences, from temperature variations or from blade deflection variations, variations in air density, wind condition yaw error, wind shear, temperature changes, alternating wind speeds etc. The pitch system may therefore be regarded as a non-linear system with varying parameters.
One problem of said system is that said varying parameters may result in a deteriorated control of the rotor blades and in turn unnecessary fatigue in the wind turbine.
It is an object of the present invention to provide an advantageous method of controlling one or more pitch actuators of a wind turbine without the above mentioned disadvantages.